(1) Field of the Invention
The present invention concerns a system for fixing a cutting head to an adapter of a machine tool, a cutting head and an adapter. The invention is intended for use in connection with boring bars and all other similar tool holders used in machine tools. The present invention is particularly adapted for boring bars for internal and external turning.
(2) Description of Related Art
During turning, vibrations or chatter, occurs due to the natural frequency of a tool being in the same area as the naturally occurring oscillations of the shear forces where the cutting takes place. This creates poor quality of the finished surface, noise and work piece poor accuracy. Technology has been developed to attenuate such vibrations by optimizing the ratio between strength and mass of the cutting head. This technology is described in patent number U.S. Pat. No. 7,121,768 of the applicant. The cantilevered length can be increased with this technology. Such cutting heads are intended to be clamped to an adapter or a boring bar.
During machining with a machine tool it will, in many cases, be desirable to change a cutting head quickly.
From the patent literature holders for cutting tools of various type are known. U.S. Pat. No. 3,811,162 discloses a clamping holder including a longitudinal track with a dove tail shaped cross section for in a longitudinal direction to take up a cutting tool with a quadratic steel bar to be secured to the notch, and that it includes a wedge-shaped liner that is clamped to this notch. Wedges and screws are shown to secure the tool. This patent, however, does not describe adapters and cutting heads for boring bars.
U.S. Pat. No. 5,322,395 discloses a tool with a body defining a first seat secured to an anvil. A cutting insert is held with a clamping body or a holding jaw.
U.S. Pat. No. 4,599,923 discloses a tool holder having a dove tail shaped fixing part for connection to a tool holder. A wedge is used to hold the tool to the tool holder.
EP 1,243,365 discloses a tool holder for boring bars where a tool is put into a groove with various angles for jamming the tool.
None of these publications describe a system for fixing a cutting head to an adapter for a machine tool that is optimized in relation to strength and mass to reduce the limitations in maximum cantilever length, in combination with a fixing system that allows quick change of the cutting head and that provides an infinitely variable adjustment of the F-measure of the cutting bit. The F-measure defines the distance between the centre of the adapter and the cutting bit (the point of the bit). Furthermore, the prior art fails to show a coupling mechanism or a system that is adapted such that the built length for the system not becomes excessive.